An image sensing device is a device for capturing at least one image using photosensitive characteristics semiconductors that react to light. With the increasing development of computer industries and communication industries, demand for high-quality and high-performance image sensors is rapidly increasing in various fields, for example, digital cameras, camcorders, personal communication systems (PCSs), game consoles, surveillance cameras, medical micro-cameras, robots, etc.
Image sensing devices may be broadly classified into CCD (Charge Coupled Device)-based image sensing devices and CMOS (Complementary Metal Oxide Semiconductor)-based image sensing devices. Recently, since an analog control circuit and a digital control circuit can be directly implemented as a single integrated circuit (IC), CMOS-based image sensing devices are rapidly come into widespread use.